#ifndef SQL_TRUNCATE_INCLUDED
#define SQL_TRUNCATE_INCLUDED
/* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

class THD;
struct TABLE_LIST;

/**
  Sql_cmd_truncate_table represents the TRUNCATE statement.
*/
class Sql_cmd_truncate_table : public Sql_cmd
{
private:
    /* Set if a lock must be downgraded after truncate is done. */
    MDL_ticket *m_ticket_downgrade;

public:
    /**
      Constructor, used to represent a TRUNCATE statement.
    */
    Sql_cmd_truncate_table()
    {}

    virtual ~Sql_cmd_truncate_table()
    {}

    /**
      Execute a TRUNCATE statement at runtime.
      @param thd the current thread.
      @return false on success.
    */
    bool execute(THD *thd);

    virtual enum_sql_command sql_command_code() const
    {
        return SQLCOM_TRUNCATE;
    }

protected:
    /** Handle locking a base table for truncate. */
    bool lock_table(THD *, TABLE_LIST *, bool *);

    /** Truncate table via the handler method. */
    int handler_truncate(THD *, TABLE_LIST *, bool);

    /**
      Optimized delete of all rows by doing a full regenerate of the table.
      Depending on the storage engine, it can be accomplished through a
      drop and recreate or via the handler truncate method.
    */
    bool truncate_table(THD *, TABLE_LIST *);
};

#endif
